Personification – Heaven is personified as a watchful force, symbolizing God, justice, and conscience.
"Peep" suggests an intrusive, almost childlike presence, as if heaven is spying on her sins.
Lady Macbeth fears divine intervention, showing that she knows what she is planning is deeply wrong as she is defyng the divine right of kings - making her seem evil to a Jacobean audience.
Metaphor – "Blanket" suggests something comforting, protective, and enveloping—Lady Macbeth wants darkness to shield her from guilt and consequences.
The contrast between "heaven" (light, goodness) and "darkness" (evil, secrecy) reinforces the play’s motif of light vs. dark.
Yet later, she consantly wants life as if needing its holy salvation.
Her downfall reinforces the moral message of the play—that those who defy divine order will inevitably face punishment.